The invention concerns a transmission with a transmission input shaft and a transmission output shaft and three power paths situated between the transmission input shaft and a main gear set consisting of two single planetary gear sets having four shafts depicted in order of speed as the first, second, third, and fourth shafts.
Furthermore, the invention concerns a hybrid power train for a motor vehicle comprising at least one combustion engine and at least one electric motor.
For example, a transmission of the type mentioned at the start has been disclosed in EP 0 434 525 A1. In the well-known transmission, which comprises five switching elements of which the selective operation in pairs determines various transmission ratios between the input shaft and the output shaft, six forward gears and one reverse gear have been implemented.
The applicant's patent application DE 10 2010 028 026 introduced a hybrid power train with a combustion engine and several electric motors. These hybrid power trains use a gear drive with sub-transmissions, each of which comprises a switchable gear stage. Except for a direct gear in the coaxial drive and output, the respective switchable gear stages present in the sub-transmissions are generated by exactly one single gear, for example, a cylindrical gear pair or a planetary gear. As a result, an eleven-speed countershaft transmission with coaxial output would require for the eleven gears at least eleven single gears in the form of eleven cylindrical gear pairs.
It is therefore the object of the invention to reduce the construction costs required for a hybrid power train of the type mentioned above by providing a multi-speed transmission.